wil6210: add support for device led configuration

Add the ability to configure the device led to be used for notifying
the AP activity (60G device supports leds 0-2).
The host can also configure the blinking frequency of the led in
three states.

Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>